Alternating-current-motor control.



D. mason.

ALTERNATING CURRENT MOTOR CONTROL.

' APPLICATION FILED AUG. 11, 1908.

1,066,739. Patented'July 8,1913.

whim/woes; 770% 3% 4 m 'UNI'inD STATES PATENT OFFICE.

DAVID LARSON, or YONKERS, NEW YORK,

AssIoNo-B, 'ro orrs nnnvsron COMPANY,

or .nnzss z crrY,--NEw'JERsnr, A conrom'rron or NEW JERSEY.

ALTEBNATINfiCURRENT-MOTOR CONTROL.

Specification of Letters Patent.

Patented July 3,1913.

Application filediiig-ust 11, 1908. Serial No. 447,935.-

' *as applied to an alternating current motor used to-operate an elevator system.

()ne'of the objects of the invention is theprovision of improved means for controlling the. starting resistance of the motor.

Other objects of the invention will appear hereinafter,- the novel combinations of elements being set forth in the appendedclaims. Referring to the accompanying drawings, Figure l is a diagrammaticview of an elevator system and the controlling and operating circuits andmec'hanisni for the motor;

Fig. 2 is a: sectional elevation ofan automatic controller for the starting resistance; and Fig. 3 is. a sectional. plan View of the same. i Y

The motor M is geared to the hoisting drum D by means of a Worm and worm' wheel (not shown). The car C is connected to the drum by hoisting ropes or cables 1 engaging the overhead sheave 2, the vibrator sheave 3, and wound around the drum. The counterweight W is connected to the-hoisting drum by cables 4. woiind around the drum in the opposite direction. Themotor brake B has its magnet circuits connected in parallel with the stator of the motor so asto receive current and release the brake in a well known manner whenever the motor receives current. This elevator system is shown merely to illustrate one of the various uses to which the motor may be applied.

Although theinvention is herein shown as used in connection with a three-phase alternating current motor, it will be understood that it is also well adapted for use with motors using currents of other phaw or direct'currents 1 The electric system here shown com rises a transformer T, reversing switches R, a car-switch S, starting resistance A, magnetic switches E, F, G, H cont/m the; circuits of; the starting. resistaudi,

an automatic controller 'K' contronni the magnet circuits of theswitches E, F, a, H. The controller K, shown in'detail in Figs.

2 and 3, comprises a stationary frame .5, a 1 shaft 6 jou-rnaled therein, and a cylindrical block or disk 7 of insulatingmaterial fixed to the shaft. secured on one end of the bloclc7 and completely surrounds the same. This ring has A metal contact ring 8 is an extension or contact arm 9 whichextends across the block 7 -to the end opposite the ring. A spring pl'essed contact l0 mounted in the frame 5 bears continually on the ring 8, and three similar contacts 11, *12 and 13 bear on the insulating block 7 in position to successively engage the contact 9 as the. block is rotated A. spr0cket wheel-14;. secured to the shaft 6 is connected bya sprocket chain 15 to the sprocket wheel 16 keyed to the shaft ofthe' oisting- .drum. D so that the shaft 6 rotates whenever the motor is running.

The primary of the transformer T is connected to any suitable source of current ,supply, and the secondary is connected through the main line switch 17 to the leads a, 6,0. The lead bis connected directly to a terminal of the stator winding of" the mo- I tor, while the leads a and care ada ted to be connected to the motor through t erevers- ;i-n switches.

hen it is dsired to start the" motor to lift the car, for example, the operator in the car moves the lever of the car switch -S to the left so that the contact 18" on the switch lever bridges the contacts 19, 20. This completes a circuit through the magnet coil of the reversing switch R as follows 'from the lead I) through conductor 21, magnet coil 22 of reversing switch R, conductor 23, contacts 19, 1'8, 20, and conductor 24 to the lead a. The reversing switch R- is therefore closed and completes'a circuit' as follows:- vfrom the lead a throughv switch contacts 25,

26, conductor a", stator windings of the motor, conductor 0', switch 'oontacts27, 28 to the lead 0. The stator of the 'motornow receives current and induces a current in the rotor and starts the motor.- The starting resistance A; is at this time all connected in circuit with-the rotor, the terminals 2, 31,???

of the resistance being connected. -by co I doctors 30, 31 and 32, respectively, to-1h.

collectorflivitigs of the motor. The

resistance "A comprises sections V, V, V controlled by'the switch E, sections X, X

X controlledby theswitchF, sections Y,

Y, Y controlled byth'e switch G,- and sections Z, Z, Z fcontr'olled bythe switch H,

the latter switch also controlling the entire resistance.

The junctions between the sections V X,

X Y and Y Z are designated respectively w,,w'and y. The junctions between the other sections ofthe resistance are correspondingly designated. Conductors 33, 34 and 35 lead from the junctions 0,1), 0 to the'contacts '19, o, '0", respectively, of-the'switch E.

Conductors 36, 37, 38"connect the junctionsra, x, m to the contacts m, as, m, respectively,

of the switch E are connected respectively to" contacts v 0, if of switch F by conductors 42, 43, 44, and the contacts 02 m and w of the switch F are connected to thecontacts af", as and an? of switch G by con ductors 45, 46 and 47.

\Vhenthe motor is started as above described, the controller K commences to r0 tatc in a counter-clockwise direction. Assuming the controller to start from the position indicated in Figs. 1 and 2, the-first step in the controlling operation will take place when the contact arm 9 runs under the brush 13. This will close a circuit through the magnet coil of switch F as follows tion Of L from the conductor 0 through conductor 48, contact 10, ring -8, contacts 9, 13, conductor 49, magnet coil 50 .ojtswitch F, conductor 51., back switch contacts 52, and conductor 53 to the lead 6. The switch F now lifts its magnet core-and brings the contacts x, :0 and II/ against the contactso 21, and 11, respectively, thereby shortcircuiting the sections of resistance X, X, X through the connections already described. The shortcircuit across the resistance X, for example, ma y be traced from the junction as through conductor 36, contacts :21, v conductor 42, conlact '11", conductor 33 to junction 0. The resistances X, X, X being shorhcircuited, the current in the motor is increased and permits an increase in speed. The operahe switch F also establishes a holding circuit for its magnet coil through conductors 48, 54, contacts 55, conductor 56, magnet coil 50, conductor 51, contacts 52, and conductor 53. The magnet F will therefore be held closed independently of controller I; which only maintains the circuit through the contacts 9, 13 for a short time. The next step occurs when the contact 9 of the controller K reaches the brush 11. This establishes'a circuit through the magnet winding of switch E as follows through conductor 48, brush 10, ring 8, contacts 9, 11, conductor '57-, magnet coil 58,-

conductors 59, 51,--switch 'con tacts 52 and:

conductor 53. Theoperation of the switch E short-circuits the sections V, V, V of the startingresistance. The short-circuit across the resistance V, for example, may be traced from the center or zero point 0 of the start-- ing resistance, through conductor 60 to the 7 lower contacts 61 of the switch E, thence through contact '0 and conductor 33 to the junction '1). The sections V" V are-likewise short-drcuit'ei The resistance bein' "thus reduced permits a further acceleration of the motor. The operation of theswitch E alsohestablishesa holding circuit'for its magnet by way" of conductors 48, 62, contacts 63, conductors" 64, C011 57, coil 58, conductors 59, 51, switch 52- and conductor 53. The-next, step takes place when tliecontact 9 runs under the brush 12. 'Thiscloses a circuit for the magnet of switch G- as follows z-through conductor 48, brush 10, ring 8, contact 9, brush 12,-conductor 65, magnet coil 66, conductors 67, 51, switch 52, and conductor 53* The operation of the switch G brings the contacts 3 y" and y into engagement with the contacts 2?, 2 and 2, respectively, and thereb'yfshort-cir- 5 cuits the resistances YfY, Y. The short-- circuit across the resistance Y,;for example,

-may be traced from the junction w through conductors 36, 45 contacts zfly, and con? ductor 39 to junction'y. A holding circuit for the magnet. coil of switch G is also es tablished byway of conductor 48, contacts entire resistance A by way of the conductors 42, 43 and 44, permitting the motor to run up to full normal speed. -The switch H closes a holding circuit through its-magnet by way of conductors 48, -76, contacts 77, conductor 74, coil 75, and c onduct0r,53. The operation of the switch H also opens the back switch 52 and as each of the circuits for the magnets of switches E, F and G includes the switch 52, the electro-magnet1c switches E, F and G will each be opened, leaving only the switchH closed. The continued operation of the controller K will have no further efl'ectvon the circuits controlled thereby. The switch H will remain clo ed until the reversing switch R is opened, w en all current will be cut on from the motor and controlling mechanism, the brake will-be applied, the motor brought 1 to rest and the controlling mechanism restored to its original condition.

' It will be noted that each of the switches E, F and G controls a certain portion of the starting resistance A independently of the other switches, so that it makes no difference in what orderxthe switches are operated. The order in which they operate depends of course on. the position in which the controller K may happen to be whenthe car is stopped. It should also be noted that the operation of the switch H-can take place only when all'three of the accelerating magnets E, F, G have operated,

regardless of the order of operation. Theoperation of the magnets depends on the load on the motor; thatis, if there is'a heavy load, the acceleration of the motor will be comparatively slow and the controller K and magnets will operate more slowly so that an excessive current will not be thrown on the motor before it has time to speed up. Each of the accelerating magnets, when once operated, is held closed independently of the speed or potential of the motor armature.

It will be understood that any number of accelerating magnets, more or less than that shown, may be used if desired, the principles and method of operation remaining the same. Various changes also in thedetails and arrangement of parts may be made I without departing from the spirit and scope of the invention,-and I wish therefore not closed.'

What I claim as new anddesire to secure by Letters Patent of the United States is 1. The combination with a sectional starting resistance, of a plurality of electro-magnetic switches independently controlling dif- -to be limited to the exact construction disk ferent sections of the resistance, an electro-- sistance, and switch contacts operated by each of said switches and included in series in themagnet circuit of'said electro-magnetic switch.

3. The combination with a sectional resistance, of a plurality of accelerating magnets, a normally closed switch common toall of said magnets, means for successively operating said magnets in different orders of sequence, and an electro-magnetic switch controlling the .sectional resistance and operatively connected to said normally closed switch.

4. The combination with a sectional resistance, of electro-magnetic switcliesfcontrolling independent-sections of the resistv ance and operable successively in different orders, a switch controlling the entire re-' sistance, a normally closed switch in a circu-it common to the magnet windings of saidelectro-magnetic switches, an electro-magnet operatively connected to the two last-named switches, and means for operating said magnets and switches.

5. The combination with an electric motor, of startingresistance therefor, and a controller controlling the acceleration of the motor and comprising a rotatable and a stationary member carrying cooperating contacts, said rotatablemember being geared to the motor to make a complete rotation during the initial movement of the motor.

6. The combination with an electric motor, of sectional starting resistance therefor,

a rotary controller, and mechanism electrically controlled thereby for. successively short-circuiting the sections of, resistance when the controller is started from any position. v

7. The combination with an electric motor, of sectional startingresistance therefor,

a rotary controller, a plurality of accelerat-.

ing magnets, and circuits and connections magnets when the controller any position. I

.8. The combination with an electric motor, of starting resistance therefor, a plurality of electro-magnetic switches controlling said resistance,. a rotary controller geared to the motor and rotatable continuously with the motor, circuit connections between the controller and the magnet wind ings of said switches for effecting the successive operation of the switches when the controller is rotated, and means for mainis started from for effecting the succesive operation of said taining the switches in their operated pO- sitions independently of the controller.

In testimony whereof, I have signed my v name to this specification in the presence of two subscribing witnesses. 5

g DAVID LARSON. Witnesses:

6 CHAS. M. NIssnN, J AMES D. Ivsns.

002!" of this patent may be obtained (or five cents each, by addressing the Commissioner of Patents, .Washingttin,1|). C." 

